Ansche Chesed, a synagogue in New York City, holds a series of dances on Sundays about once a month. Each Sunday is a different dance style. They have a nice wooden floor (although be forewarned that it is a fast floor, so if you are wearing ballroom shoes, make sure to brush them out) surrounded by carpet. The event I attended had at least 70 people at the beginning, with a few more arriving later. The room was full and the dance floor was crowded with enthusiasm, but still had enough space to dance comfortably. Most of these events have a live band and a professional demonstration, as well as a lesson at the beginning. The lesson is taught by Reba Perez, who does a great job introducing each dance. The events are primarily intended as Jewish singles events (it is in a synagogue, after all), but no one need feel excluded. There were people of a range of ages in attendance. They serve soda, wine and cookies. Admission is $20 ($15 for members of Ansche Chesed, B'nai Jeshurun or Mosaic Outdoor Mountain Club). Call ahead to find out dates of future events. Who knows, you might meet someone.